The spore coat of Bacillus subtilis is made up of a mixture of polypeptides largely of molecular weights less than 12,000 daltons. About one third of the protein is cross-linked but at least two of the low molecular weight proteins can be purified and antibodies produced. These antibodies will be used to determine the time of synthesis and presence of any precursors to these proteins. Cross linking experiments will also be done to establish the proximity of these proteins to each other in the various spore coat layers. Two classes of mutants altered in spore coat formation will be studied with similar techniques. One class appears to be defective in a specific intracellular protease so the role of these enzymes in sporulation and in metabolic events in post-exponential cells will be studied. A possible function of glutamine synthetase in sporulation and in the regulation of catabolism in B. subtilis will be further studied. Various cold sensitive glutamine auxotrophs will be analyzed genetically and biochemically to establish the basis of the conditional phenotype and possible altered regulatory properties.